A theory that suggests the aging process might be safely slowed by targeting genes that are quiet early but threaten damage later in life has gotten a boost from new findings from the University of Illinois at Urbana-Champaign.

Share This

CHAMPAIGN, Ill. -- A theory that suggests the aging process might be safely slowed by targeting genes that are quiet early but threaten damage later in life has gotten a boost from new findings from the University of Illinois at Urbana-Champaign.

Related Articles

The researchers don't promote such tinkering in their paper, which appears online this week in advance of publication by the Proceedings of the National Academy of Sciences. Rather they detail their tests, based on models of mathematical prediction, of the two leading evolutionary theories of aging on the reproductive success of 100 different genotypes of fruit flies (Drosophila melanogaster) across various age groups.

The results suggest that more needs to be learned about which genes do what and when in the aging process so that artificial manipulation does not cause evolutionary damage in future generations, said Kimberly A. Hughes, an animal biologist in the Program in Ecology and Evolutionary Biology at Illinois.

The study provides the strongest support yet for the theory of mutation accumulation (MA), Hughes said. The theory, which has been difficult for scientists to test, proposes that aging is the result of an accumulation of mutations of genes that are kept in check by reproductive-oriented selection processes early in life and only are active later on.

Examples are genes associated with Huntington's disease and forms of cancer that strike late in life. Such mutations exist in prime reproductive years but only have noticeable effects late in life. In old age, when reproduction is not an organism's primary function, accumulating mutations are no longer checked by selection, increasing the risk of disease.

The other, more widely accepted theory of antagonistic pleiotrophy (AP) says that aging occurs when genes that offer help during the reproductive years -- those that produce estrogen, for example -- take on harmful roles later in life. Selection under AP theory favors the early life effects because these lead to the production of offspring but does not oppose the deleterious effects in late life, Hughes said.

Building on her theoretical study of age-related inbreeding depression and genetic variability (PNAS, June 1996) while a doctoral student at the University of Chicago, Hughes and colleagues raised fruit flies to test the effect of delayed mutations.

The new study found that the deleterious effects of mutations on reproduction rose dramatically with age during the reproductive years in both genotypes -- homozygous (those with many identical genes, or inbreeding) and heterozygous (those having a variety of genes present). Reproductive success declined more rapidly, however, in the homozygous lines, as predicted by the MA theory.

"This study allowed us to detect certain kinds of genetic effects called dominance variance that are predicted to increase with age only under the MA theory," Hughes said. "The power to detect these effects is critical to tests of evolutionary aging theories, because an age-related increase appears to be a unique prediction of the MA theory, while other kinds of genetic effects can increase under either model."

While the study shows support for the MA theory, the scenario under the antagonistic pleiotrophy theory is not discounted. "They are not mutually exclusive,Ó Hughes said. "They can both be happening. Both kinds of genes can be accumulating.Ó

If geneticists try to remove bad late-in-life effects of a gene that has a positive role early in life, then its overall function could be negatively altered in future generations, Hughes said. Manipulating genes with no early life benefits to negate their deleterious late life effects, she said, might not cause negative evolutionary changes in the future.

The authors of the paper are Hughes, postdoctoral researcher Jenny M. Drnevich and doctoral student Rose M. Reynolds, all of Illinois, and former postdoctoral associate Julie A. Alipaz, who now is at Harvard University.

The National Science Foundation, National Institutes of Health and the School of Integrative Biology at Illinois funded the research.

More From ScienceDaily

More Health & Medicine News

Featured Research

Mar. 3, 2015 — Scientists have discovered a new hormone that fights the weight gain caused by a high-fat Western diet and normalizes the metabolism -- effects commonly associated with exercising. When tested in ... full story

Mar. 3, 2015 — New assays can detect malaria parasites in human blood at very low levels and might be helpful in the campaign to eradicate malaria, reports a new study. An international team led by Ingrid Felger, ... full story

Mar. 3, 2015 — Adults over the age of 30 only catch flu about twice a decade, a new study suggests. So, while it may feel like more, flu-like illness can be caused by many pathogens, making it difficult to assess ... full story

Mar. 3, 2015 — No significant change in home habits of smokers have been observed in the aftermath of a ban on smoking in public spaces, researchers report. Greater inspiration to kick the habit likely comes from ... full story

Mar. 3, 2015 — Heart function has been associated with the development of dementia and Alzheimer's disease through a new study. Participants with decreased heart function, measured by cardiac index, were two to ... full story

Mar. 3, 2015 — Children of recently separated or divorced families are likelier to drink sugar-sweetened beverages than children in families where the parents are married, putting them at higher risk for obesity ... full story

Mar. 3, 2015 — Gastric bypass and similar stomach-shrinking surgeries are a popular option for obese patients looking to lose weight or treat type 2 diabetes. While the surgeries have been linked to a decreased ... full story

Mar. 3, 2015 — Most people consume more salt than they need and therefore have a higher risk of heart disease and stroke, which are the two leading causes of death worldwide. But a new study reveals that dietary ... full story

Featured Videos

Mom Triumphs Over Tragedy, Helps Other Families

AP (Mar. 3, 2015) — After her son, Dax, died from a rare form of leukemia, Julie Locke decided to give back to the doctors at St. Jude Children&apos;s Research Hospital who tried to save his life. She raised $1.6M to help other patients and their families. (March 3)
Video provided by AP

Looted and Leaking, South Sudan's Oil Wells Pose Health Risk

AFP (Mar. 3, 2015) — Thick black puddles and a looted, leaking ruin are all that remain of the Thar Jath oil treatment facility, once a crucial part of South Sudan&apos;s mainstay industry. Duration: 01:13
Video provided by AFP

Woman Convicted of Poisoning Son

AP (Mar. 3, 2015) — A woman who blogged for years about her son&apos;s constant health woes was convicted Monday of poisoning him to death by force-feeding heavy concentrations of sodium through his stomach tube. (March 3)
Video provided by AP

Related Stories

July 17, 2014 — It is something of an eternal question: Can we slow or even reverse the aging process? Even though genetic manipulations can, in fact, alter some cellular dynamics, little is known about the ... full story

May 5, 2011 — A new study identifies the mutation that underlies a rare, inherited accelerated-aging disease and provides key insight into normal human aging. The research highlights the importance of a cellular ... full story

Dec. 20, 2010 — It sounds like science fiction -- scientists tested the current "free radical theory of aging" by creating mutant worms that had increased production of free radicals, predicting they would ... full story

July 6, 2010 — A new study casts doubt on the theory that oxidative stress shortens lifespan. Researchers have identified mutations in 10 different genes of worms (genes believed to have counterparts in humans) ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.